These equations tell us that u1 - u2, u1 - u3, and u2 - u3 are in the nullspace of T.
Find these vectors, and find a subset of them that is a linearly independent set. From those vectors you can get values for the entries of the matrix corresponding to the transformation T.

and built an equations T*U1=(1,1) T*U2=(1,1) T*U3=(1,1)
so i get for "a" parameters only 3 equations
which is not enough
how to use the data that those vectors are independant
in order to build the 4th "a" parameter equation

Staff: Mentor

You say you solved it differently, but you're still asking questions, so it doesn't sound like the problem is actually solved. On the other hand, I actually found a matrix A for which A*u1 = [1 1], A*u2 = [1 1] and A*u3 = [1 1], so which is the better solution?